The objective of this study is the development of a simple and reproducible technique for the analysis and documentation of fractured dental porcelain surfaces which have broken in the mouth. The goal is to develop a technique which can be used in a subsequent study (not part of this grant application) for the determination of causes of clinical fracture of porcelain restorations. Fractographic methodology will be used to study laboratory induced fractures of procelain restorations, and the techniques developed will be used to evaluate fracture surfaces of porcelain which has broken in the mouth. Techniques for the replication of fracture surfaces, enhancement of fracture surface detail, and photographic methodology will be developed. Examples of various types of flaw initiated fracture will be photographically documented, and samples will be analyzed for the origin of fracture, and direction of fracture propagation. As an important part of this study, the results of fractographic analysis of the fractured porcelain surfaces will be compared to the results obtained from replicas of those surfaces. The objective of using replicas is to provide a reliable technique for performing fractographic analysis of broken porcelain restorations which cannot be removed from the mouth for direct observation. Fracture of porcelain restorations can cause a loss of function and esthetics, can endanger the health of an individual, and can increase the cost of care. As a result of this study, it will be possible to use fractographic analysis to determine the predominant cause(s) of fracture of dental procelain restorations in a subsequent study. This will ultimately lead to a better understanding of what future directions of research are necessary in order to reduce the frequency of clinical fracture of dental porcelain restorations.